DE102005056329A1 - Method for controlling a motor vehicle system - Google Patents

Abstract

The invention relates to a control system (18) and a control method for motor vehicles (10) having a pitch rate sensor (37) generating a pitch rate signal, a longitudinal acceleration sensor (36) generating a longitudinal acceleration signal, and a yaw rate sensor (28) generating a yaw rate signal wherein a security system (44) and the sensors are connected to a controller. The controller (26) determines from the sensors an added mass and the added mass position, a pitch gradient and / or pitch acceleration coefficient that takes into account the added mass and position and controls the vehicle according to the added mass and the added mass position, the pitch gradient and / or the pitch acceleration coefficient variable.

Description

The The invention relates generally to a method of controlling a motor vehicle system according to a measured dynamic behavior. It relates refers to a procedure for a rear vehicle load and / or the Influence of Vehicle load to determine the control device of the vehicle.

Recently Vehicle roll stability control (RSC) schemes are proposed in U.S. Patent 6,324,446 to process friction-induced flashovers. RSC systems include many sensors that measure vehicle conditions and a controller that controls a distributed brake pressure reduce the tire force so that the net moment of the vehicle the rolling direction counteracts.

During one Event that causes a rolling of the vehicle is the Vehicle body a rolling moment due to the coupling of the lateral Tire force and lateral acceleration pointing to the center of gravity the vehicle body is applied, subjected. This rolling moment causes a suspension height variation, which in turn leads to a relative vehicle roll angle (also referred to as chassis roll angle or suspension roll angle). Of the relative roll angle is an important variable used as input for activation criteria is inserted, and the response pressure command To construct, as he the relative roles between the vehicle body and the axis absorbs. The sum of the chassis roll angle and the Rollwinkel between the vehicle axle and the road surface (Radabhebewinkel called) provides the roll angle between the vehicle body and the middle road surface, the one the important variable that is the Roll Stability Control module feeds back. Trucks, off-road vehicles and passenger cars are sometimes used to carry heavy loads. For example, a fully loaded truck, loaded at the back, a trunk of a passenger car can be loaded and an off-road vehicle or Van can be loaded in the rear. The rear cargo can be the vehicle because of the increased Load to nod.

A size rear / trunk load (additional Mass) can the lateral forces saturate on the rear axle of the vehicle, causing the vehicle rather tends to oversteer. In stability criteria can a GWAR (large Weight on the rear axle), cause the vehicle to move while some aggressive maneuvers with a great To move side slip angle. If the vehicle with a very large lateral Rutschwinkel glides, device it in the non-linear range of vehicle dynamics; the vehicle could tip over and overturned. It is for a normal driver extraordinarily difficult to control and the vehicle dynamics controls must be activated become. As a result, would be it wanted the tax authority in stability controls to adjust so that improved behavior of a vehicle with a large trunk load or rear load is reached.

A size Vehicle trunk cargo may also have a negative effect have the vehicle sensor readings. For example, the Trunk load Vehicle pitch down towards the rear axle cause. Such load-induced pitching can be faulty Readings of a pitch rate sensor, a yaw rate sensor and a Longitundinal acceleration sensor effect. As a result, it is he wishes, Such load-induced pitch misalignment based on detected boot load or rear load and to use this information, the sensor signal outputs to compensate. Such a trunk load induced pitch misalignment Can also be used to control the vehicle body level to guide and adjust the orientation of the front lamps.

It is therefore an object of the invention to provide a system for characterizing chassis pitch that can be used in conjunction with the various vehicle systems, including, but not limited to, a roll stability control system, yaw stability control, front light level control, and vehicle level control. In the stability controls, the boot load can be used to determine the exact trends of vehicle nodding for vehicles and adaptively adjust the pitch angle calculation and / or adaptively set the activation criteria for the stability control system. In particular, the invention may determine an additional mass and the position of the mass or the effect of the additional mass and its position. This means that a relatively small mass change can significantly affect the directional dynamics of the vehicle. A rear or trunk load can affect vehicle dynamics and lateral dynamics while increasing vehicle oversteer characteristics. The control system can then determine how the various actuators are going up Control sense, to more aggressively correct the potentially unstable condition, or in a weakening sense, to mitigate actuator influence for correcting potentially erroneous activations.

It is therefore an object of the invention, an improved vehicle dynamics control to enable.

The Task is achieved by a method having the features of claims 1, 2, and 7 solved. advantageous Further developments emerge from the dependent claims.

One Aspect of the invention comprises a method for controlling a vehicle, with determination of a pitch gradient and / or a pitch acceleration coefficient. This means that the pitch gradient and the pitch acceleration coefficient can be used individually or in combination Vehicle system, such as a security system to control.

According to one Another aspect of the invention includes a method of control a vehicle safety device determining a compound Parameters, referred to as pitch gradient, determination of another composite parameter, as pitch acceleration coefficient Designating an added mass, the position of the added mass of the pitch gradient and the pitch acceleration coefficient, and controlling the vehicle system according to the added mass and their position.

According to one Another aspect of the invention includes a motor vehicle control system. a pitch rate sensor that generates a pitch rate signal, a Longitudinal acceleration sensor, which is a longitudinal acceleration signal generated and a yaw rate sensor that generates a yaw rate signal. A security system and the sensors are with a controller coupled. The controller determines an added mass and the Position of the added mass from the roll rate, the longitudinal acceleration and the yaw rate and controls the security system accordingly the loaded mass and its position.

One Advantage of the invention is that the vehicle trunk space loading state detected and can be determined very accurately. Such loading conditions can can not be determined exactly by the vehicle longitudinal dynamics, As in some existing procedures, the vehicle torque and the vehicle longitudinal acceleration for calculating the vehicle mass use.

Further Advantages and features of the invention will become apparent from the following detailed description of a preferred embodiment, in particular together with the attached drawings and claims.

It shows

1 a diagrammatic view of a vehicle with coordinate frame;

2 a block diagram of a stability system according to the invention;

3 a front view of a motor vehicle with different angles;

4 a side view of a motor vehicle in pitch with different variables;

5 a plan view of a motor vehicle with variables that are used in the following calculations;

6 a detailed block diagram of a controller according to the invention; and

7 a flow chart of an operating method according to the invention.

In the following figures, the same reference numerals are used to identify the same components. The invention can be used in conjunction with a roll control system for a vehicle. The invention can also be used with a triggering device, such as an airbag, an active roll bar or firming straps. The invention could provide information to an adaptive travel control system or to a collision avoidance system based on brakes to change the braking demand levels of the system. The invention will be discussed below with reference to preferred embodiments relating to a vehicle moving in a three-dimensional road terrain. The invention will be described with regard to the determination of an added mass and the position of the charged mass. Nevertheless, as described below, the added mass and its position can not be determined directly instead by adaptively updating a pitch state parameter such as a pitch gradient value and / or a pitch acceleration coefficient, the effects of the loaded mass and the position of the loaded mass contained in those values may be included. Such values may also be referred to as "adaptive" pitch gradient and "adaptive" pitch acceleration coefficient. The different pitch parameters may be referred to as adaptively determined values, which means that these values may change over time due to changes in mass or payload. This means that these values are not fixed and the values can be updated when the vehicle is moving or driven. The values can then be averaged.

Remarkably, can, although the pitch gradient or the pitch acceleration coefficient can be determined adaptively the other values are not adaptive.

In 1 is a motor vehicle 10 with a safety system according to the invention with the various forces and moments acting thereon during a dynamic state. The vehicle 10 has front right (FR) and front left (FL) wheels / tires 12A and 12B and rear right (RR) wheels / tires and rear left (RL) wheels / tires 13B , The vehicle can also have several different types of front steering systems 14A and rear steering systems 14B including those in which each front and rear wheel is configured with a corresponding controllable actuator; those in which the front and rear wheels have a conventional system in which both front wheels are controlled together and both rear wheels are controlled together, in a system with conventional front steering and independently controllable rear controls for each wheel or vice versa. Generally, the weight of the vehicle is represented as Mg at the center of gravity of the vehicle, where g = 9.8 m / s ² and M is the total mass of the vehicle.

As explained above The system can also be equipped with safety systems, including active / semi-active suspension systems, roll bars, airbags and other safety devices that are predetermined when measuring dynamic states of the vehicle or activated, can be used.

The measuring system 16 is with a tax system 18 connected. The measuring system 16 For example, a variety of sensors, including the sensor set typically included in a vehicle stability control or roll control system (including a lateral accelerometer, yaw stability sensor, steering angle sensor, and wheel speed sensor equipped for a traditional stability control system), may be used in common with a roll rate sensor and a longitudinal accelerometer. The various sensors are explained in more detail below. Sensors may also be used by the control system in various determinations, such as determining liftoff, determining the position of a mass, and so on. The wheel speed sensors are mounted in each corner of the vehicle and generate signals corresponding to the rotational speed of each wheel. The rest of the sensors of the measuring system 16 can be directly at the center of gravity of the vehicle body along the directions x, y and z, as in 1 shown to be attached. It will be apparent to those skilled in the art that the frame of b ₁ , b ₂ and b _{3 are} body frames 22 b _{1 of} the forward x-axis, b ₂ in the direction of travel directed y-axis (to the left) and b ₃ in the z-axis, pointing upwards, equivalent. The angular velocities of the vehicle body are referred to their respective axes as ω _x for the roll rate, ω _y for the pitch rate and ω _z for the yaw rate. Calculations can be done in an inertial frame 24 take place from the body frame 22 , as explained below, can be derived.

The angular velocity sensors and the accelerometers may be disposed on the vehicle body along the body frame directions b ₁ , b _2, and b ₃ , which are the x, y, and z axes of the sprung mass of the vehicle.

The longitudinal acceleration sensor is attached to the vehicle body at the center of gravity, with its measuring direction along the b ₁ axis and whose output is referred to as a _x . The lateral acceleration sensor is mounted on the vehicle body at the center of gravity, with its measuring direction along the b ₂ axis, whose output is referred to as a _y .

The other frame used in the following discussion includes the road frame as in FIG 1 shown. The road frame system r ₁ , r ₂ , r ₃ is fixed on the traveled road surface with the r ₃ axis along the average normal road direction calculated from the normal directions of the four tires / road contact surfaces.

In the following discussion, the Euler angles of the body frame b ₁ , b ₂ , b ₃ and the road _frame r ₁ , r ₂ , r _{3 are} referred to as θ _xbr and θ _ybr , also referred to as relative Euler angles (namely, relative roll and pitch angles).

In 2 the roll stability system is shown in more detail, with a control 26 for receiving information from sensors, including a yaw rate sensor 28 , a speed sensor 20 , a lateral acceleration sensor 32 , a vertical acceleration sensor 33 , a roll angle rate sensor 34 , a steering wheel (handwheel) angle sensor 35 , an angular acceleration sensor 36 , a pitch rate sensor 37 , Steering angle (wheels or actuator) Position sensor 38 , Suspension load sensor 40 and a suspension position sensor 42 , Of course, various combinations and sub-combinations of sensors can be used.

The speed sensor 20 may be from a variety of speed sensors known in the art. For example, a suitable speed sensor may include a sensor on each wheel that is controlled by the controller 26 is averaged. The controller can translate the wheel speeds into vehicle speed. Yaw rate, steering angle, wheel speed, and possibly a slip angle estimate on each wheel can be recalculated into the speed of the vehicle's center of gravity. Various other algorithms are known to those skilled in the art. The speed can also be obtained from a transmission sensor. For example, if the speed is determined during acceleration or braking around a corner, the lowest and highest wheel speeds may not be used due to their faultiness. It is also possible to use a transmission sensor for determining the vehicle speed.

The roll angle rate sensor 34 and the pitch rate sensor 37 may determine the roll condition or lift off of a vehicle based on the measurement of the height of one or more points on the vehicle relative to the road surface. Sensors that may be used include, but are not limited to, radar proximity sensors, laser proximity sensors, and sonar proximity sensors. The roll rate sensor 34 can also use a combination of sensors, such as proximity sensors, to perform a roll rate determination.

The roll rate sensor 34 and the pitch rate sensor 37 may also measure roll state or lift based on measuring a linear or relative rotational displacement or displacement speed of one or more suspension chassis components. This may be in addition to or in combination with the suspension position sensor 42 respectively. The position sensor 42 , the roll rate sensor 34 and / or the pitch rate sensor 37 For example, a linear height and travel sensor, a rotation height or travel sensor, a wheel speed sensor to determine a speed change, a steering wheel position sensor, a steering wheel speed sensor, and a driver control input of an electronic component that include wire steering using a hand wheel or a joystick can, include.

The roll condition or lift may also be accomplished by directly measuring or estimating the force or torque associated with the load condition of the suspension or chassis components, including a pressure transducer in an air suspension, a shock absorption sensor such as a load sensor 40 , a tension meter, the absolute or relative engine load of the control system, the control system pressure of the hydraulic lines, a tire lateral force sensor or sensors, a longituitional tire force sensor, a vertical tire force sensor, or a tire sidewall torsion sensor. The yaw rate sensor 28 , the roll rate sensor 34 , the lateral acceleration sensor 32 and the longitudinal acceleration sensor 36 can be used together to determine that a wheel has lifted off. Such sensors can be used to determine the liftoff of a wheel or to estimate the normal load associated with the wheel lift. These are also passive procedures.

The roll condition of the vehicle may also be determined by one or more of the following; Translational or rotational positions, speeds or acceleration of the vehicle, including a rollgyro, the roll rate sensor 34 , the yaw rate sensor 38 , the lateral acceleration sensor 32 , the Ver tikalbeschleunigungssensor 33 , a vehicle longitudinal acceleration sensor 36 , Lateral or vertical speed sensors, including a speed sensor 20 based on wheels, a radar-based speed sensor, a sonar-based speed sensor, a laser-based speed sensor, or an optical-based speed sensor.

at the preferred embodiment the sensors are located at the center of gravity of the vehicle. The expert is obvious that the sensor is also opposite the center of gravity shifted and equivalent can be offset.

Lateral acceleration, roll orientation and speed can be obtained using a Global Positioning System (GPS). Based on the inputs of the sensors, the controller 26 a safety device 44 Taxes. Depending on the desired sensitivity of the system and various other factors, not all sensors need 28 - 42 be used in a commercial embodiment.

The load sensor 40 may be a load cell coupled with one or more suspension components. By measuring the load, the stress or the weight on the load sensor, a shift of the load can be determined.

The control 26 can be a signal multiplexer 50 which is used to receive the signals from the sensors 28 - 42 to recieve. The signal multiplexer 50 delivers the signals to a Radabhebedetektor 52 , a vehicle roll angle calculator 54 and a roll stability control (RSC) feedback control unit 56 , The Radabhebedetektor 52 can also use the vehicle roll angle calculator 54 be connected. The vehicle roll angle calculator 54 can also work with the RSC feedback control unit 56 be connected. The RSC feedback control unit 56 can be a torque control 57 include. The vehicle roll angle calculator 54 is described in US Provisional Applications 60 / 400,376 and 60 / 400,172 and in US Patent Application 10 / 459,697, the contents of which are incorporated herein by reference.

A load detector 58 can also be in the controller 26 to be inclusive. The load detector 58 may be used to determine an additional mass of the vehicle and a position or longitudinal distance of the mass, as will be described below.

The security device 44 can an airbag 45 or a control actuator 46A to 46D on one or more of the wheels 12A . 12B . 13A . 13B of the vehicle. There may also be other vehicle components, such as a suspension control 48 , used to adjust the suspension to prevent rollover.

The security device 44 can change the position of the front right wheel actuator 46 , the front left wheel actuator 46B , the rear left wheel actuator 46C and the rear right wheel actuator 46D Taxes. As described above, two or more actuators can be controlled simultaneously. For example, in a rack pinion system, the two wheels connected thereto are simultaneously controlled. Based on the inputs of the sensors 28 - 42 determines the control 46 a roll state and / or Radabheben and controls the steering position and / or the braking of the wheels.

The security device 44 can with a brake control 60 be connected. The brake control 60 Controls the amount of brake torque on a front right brake 62A , a left front brake 62b , a left rear brake 62c and a right rear brake 62d , Other security systems, such as an ABS 64 , a greed stability control system 66 and a traction control system 68 can also benefit from knowledge about the pitch gradient, the pitch acceleration quotient, the additional mass and position of the mass. This information may affect the control strategy, for example braking may be modified.

The output of the control can be with a vehicle body level system 70 , a front light adjustment system 72 and a sensor signal compensation block 74 get connected. The body level system 70 can with a suspension control 48 be connected, which controls the suspension to compensate for the changes in the pitch angle due to the additional mass. The front light target direction can also be in a front light control block 72 be changed. Different sensor signals can be changed by a factor due to the reduced pitch shift.

The roll condition can be measured and modified due to the additional load. The Rollzu The position of a vehicle may be characterized by the relative roll angle between the vehicle body and the wheel axle and the wheel lift angle (between the wheel axle and the average road surface). Both the relative roll angle and the wheel lift angle may be calculated in the relative roll angle determination module using the roll rate and the lateral acceleration sensor signals. If both the relative roll angle and the wheel lift angles are large enough, the vehicle may either be in a single-wheel lift or in double-wheel lift. On the other hand, if both angles are small enough, the wheels probably will not have all ground contact. If both are not small and a Doppelradabhebezustand is detected or determined, the sum of these two angles is used by the feedback control module to calculate the desired operation command to achieve a roll control.

Of the Rolling condition of a vehicle may be due to the wheel lift roll angle Base of the rolling radius can be characterized, which is the angle between the wheel axle and the average road surface picking up the dynamic rolling radii of the right and left wheels, if both wheels are on the ground. Since the calculation of the rolling radius with the wheel speed and the linear speed of the wheel in Relationship becomes such a roll radius based one Radabhebewinkel accept abnormal values when much wheel slides takes place. This occurs if a wheel is lifted off and torque on the wheel is applied. Consequently, if this Rollradiusabhebewinkel growing fast, the vehicle lifted wheels have. A small such angle indicates that all wheels are in contact with the ground to have.

Of the Rolling condition of the vehicle is indirectly from the Radlongitudinalrutschen seen. If during Normal braking or drive torque will cause the wheels to slip one side of the vehicle more, the wheels lose on this side Longitudinalstraßendrehmoment. This induces the wheels either on a surface are driven or raised with low mu. The state of a Surface with low mu and a lifted wheel may also be based on the Chassis roll angle calculation are differentiated, d. H. at a surface With low mu, the chassis roll angle is usually very small. As a result, an exact determination of the chassis roll is desired.

Of the Rolling condition of the vehicle can be maintained by the at each wheel maintained Normal load to be characterized. Theoretically, then, if one Normal load on the wheel decreases to 0, the wheel is no longer in contact with the road surface. In In this case, a potential rollover is on the way. A special size of the load indicates that the wheel has ground contact. Normal load is a function the calculated chassis roll and pitch angle. Consequently, one is exact determination of the chassis roll and pitch angles desired.

Of the Rolling condition can be identified by the actual Street torques the on the wheels be applied and the road moments, which needed be the wheels keep in touch with the ground, be checked. The actual Wheel torque can from the torque adjustment for every wheel using the wheel acceleration, the drive torque and the braking torque are obtained. If the wheel contacts the road surface, have to the calculated actual Wheel torque equal to or greater than those from the nonlinear torques that come from the normal load and the longitudinal slides can be calculated on each wheel.

The roll condition of a vehicle may be characterized by the vehicle roll angle itself, namely the relative roll angle θ _xr between the vehicle body and the wheel axle. If this chassis roll angle is growing rapidly, the vehicle may be on the verge of a wheel lift or rollover. A small angle indicates that the wheels are not raised or have all ground contact. As a result, an accurate determination of the chassis roll angle to determine whether the vehicle is in a non-roll condition makes sense.

Of the Rolling condition of a vehicle can also be due to the roll angle between the wheel axis and the average road surface are determined, this will referred to as Radabhebewinkel. If the roll angle is growing fast, has the vehicle is a lifted wheel or wheels and it must be an aggressive control action carried out be around the vehicle at the rollover to prevent. A small such angle indicates that the wheels are not are raised.

Of the Center of gravity C is shown with a nominal mass M. A Roll axis is also shown at a distance D from the center of gravity.

a _y is the lateral acceleration.

In 3 is the relationship of the different angles of the vehicle 10 relative to the road surface 11 shown. Subsequently, a reference road banking angle θ _bank relative to the vehicle 10 shown on a road surface. The vehicle has a vehicle body 10a and a wheel axle 10b , The wheel lift angle θ _wda is the angle between the wheel axle and the road. The relative roll angle θ _xr is the angle between the wheel axis 10b and the body 10a , The global roll angle θ _x is the angle between the horizontal plane (ie at sea level) and the vehicle body 10a ,

One Another important angle is the linear banquet angle. The linear one Banquet angle is a banquet angle that is calculated more often (possibly in each loop) in which the linear roll dynamics of a Vehicle calculated relative roll angle (see U.S. Patent 6,556,908, to which full content is referred), from the calculated global Roll and pitch angles (as described in U.S. Application 09 / 789,656, which is hereby incorporated by reference) subtracted becomes. If everything changes slowly without drift, error or the like, that would be linear banquet angles and the reference street banquet angle terminus equivalent.

In the 4 and 5 is a vehicle 10 represented with different parameters on it. A change in mass ΔM is shown relative to the nominal centroid C ₀ . The center of gravity moves to C as the added mass ΔM is added. The mass change or load ΔM is at a distance H above the load floor 80 positioned. The nominal center of gravity C ₀ is located at a distance L from the added mass in the longitudinal direction. The longitudinal distance between the new centroid and the nominal centroid C ₀ is ΔL.

In 5 For example, the longitudinal acceleration is designated by a _x while the longitudinal velocity is designated by v _x . The lateral acceleration and lateral velocity are referenced correspondingly v _y a _y. The steering wheel angle is denoted by δ _w . The wheel base of the vehicle is indicated by the symbol b.

In the 6 becomes a controller 26 shown in more detail. The control 26 receives the various sensor signals, for example the pitch rate, longitudinal acceleration and yaw rate of the corresponding sensor signals. Other input signals, such as relative roll angle, flat foot index, and vehicle motion characteristics, may be determined from various other sensor signals or from a stability control system, such as a roll stability control system. The flatness index provides an indication of the flatness (slope / banquet) of the road. One way to determine the flatness index is described in US Patent 6,178,248, which is hereby incorporated by reference. The vehicle motion characteristics may, for example, provide an indication of the vehicle's movements, such as acceleration or deceleration. From the sensor signals, the load position in the longitudinal direction and the size of the load, the pitch gradient and the pitch acceleration coefficient can be determined. These values may ultimately generate a vehicle pitch compensation term that may be used to correct all sensor signals and a roll stability control system to adjust control gains and thresholds. Instead of directly determining the load and position of the load, first an adaptive pitch acceleration coefficient and an adaptive pitch gradient can be determined. Such parameters are inherently related to the load and position of the load contained therein. They can therefore be used to determine the load and the loading position. As will be described in more detail below, the controller uses 26 the pitching signal and leads a derivative in box 84 by, the pitch acceleration signal ω. _y , which then passes through the first filter 86 to the generation of the variable X is filtered. The X value is sent to the pitch gradient and pitch acceleration coefficient determination module 88 delivered. The longitudinal acceleration signal is in the second filter 90 filtered and delivered to the pitch gradient and pitch acceleration coefficient module, shown as Y. Nick rate, yaw rate and relative roll angle become a Z-determination module 92 supplied to determine the intermediate variable Z. The intermediate variable Z is in the third filter 94 filtered and the pitch gradient and pitch acceleration coefficient determination module 88 transmitted. As will be described in more detail below, the output of the pitch gradient and pitch acceleration coefficient determination module is 88 the pitch gradient and pitch acceleration coefficient associated with a load / load position detection block 96 be transmitted. The charge / load position detection block 96 generates a mass change, a position signal and a change of the position signal, according to the change of the vehicle's center of gravity. A vehicle load compensation term is displayed in the load characterization block 98 generated. The output of the charge characterization block 98 may be communicated to a stability control module and / or charge-induced pitch misalignment. The charge induced pitch misalignment can be found in the body level control system 70 , the front light adjustment system 72 and the sensor signal compensation block 74 be used.

In 7 is the operation of the controller 96 described in more detail. In step 102 The various sensors, such as the pitch rate sensor, the longitudinal acceleration sensor, and the pitch rate sensor are read. In step 103 the pitch gradient and the pitch acceleration coefficient are determined.

There are two pitch angle calculations as listed below. Finally, a pitch gradient and a pitch acceleration coefficient are derived from the relative pitch angle and the other, the global pitch angle. The relative pitch angle φ _relative is a function of the longitudinal acceleration a _x , the pitch acceleration ω. _y , the pitch gradient ρ and the pitch acceleration coefficient σ. φ relative = f (a x , ω. y ; ρ, σ) (1)

ein Filter ist, welcher das lineare Nickmodell des Fahrzeugs reflektiert. Bemerkenswerterweise benimmt sich die Fahrzeugnickbewegung während des Abbremsens und der Beschleunigung unterschiedlich. In diesem Fall sollte

unterschiedlich für Abbremsen und Beschleunigung eingestellt werden. Man beachte die Nicktransferfunktion als T_{pitch_acc}(z) während des Fahrzeugbeschleunigens und als T_{pitch_dec}(z) während des Fahrzeugbremsens. In ähnlicher Weise unterscheiden sich der Nickgradient und der Nickbeschleunigungskoeffizient von der Fahrzeugbeschleunigung und dem Abbremsen und werden als ρ^acc und σ^acc für das Beschleunigen und ρ^dec und σ^dec für das Abbremsen bezeichnet.In the z transformation: φ relative = ρT pitch (Z) a x - σT pitch (z) ω. y (2) in which

is a filter which reflects the linear pitch model of the vehicle. Remarkably, the vehicle pitching motion behaves differently during braking and acceleration. In this case should

be set differently for deceleration and acceleration. Note the pitch transfer function as T _{pitch_acc} (z) during vehicle _acceleration and as T _{pitch_dec} (z) during vehicle _braking . Similarly, the pitch gradient and pitch acceleration coefficient differ from vehicle acceleration and deceleration and are referred to as ρ ^acc and σ ^acc for acceleration and ρ ^dec and σ ^dec for deceleration.

On the flat ground, the global pitch angle φ _{globally is} a function of the pitch rate ω. _y , yaw rate ω _z , relative roll angle θ _relative, and relative pitch angle φ _relative φ global = g (ω y + ω z + θ relative + φ relative ) (3)

In z transformation φ global = T adi (Z) [ω y - ω z θ relative ] + T ssc (Z) φ relative (4) where T _adi (z) and T _ssc (z) are two filters to perform antidrift integration and steady state compensation. Remarkably, at the base level, the relative pitch angle and the global pitch angle are the same. As a result, relationships between the pitch gradient ρ and the pitch acceleration coefficient σ are given from (1) and (3) or (2) and (4). Substituting (2) in (4) during acceleration yields: φ global = T adi (Z) [ω y - ω z θ relative ] + ρ acc T ssc (Z) T pitch_acc (Z) a x - σ acc T ssc (Z) T pitch_acc (z) ω. z (5) or the following for braking φ global = T adi (Z) [ω y - ω z θ relative ] + ρ dec T ssc (Z) T pitch_dec (Z) a x - σ dec T ssc (Z) T pitch_dec (z) ω. z (6)

By equating (2) and (5) for vehicle acceleration, the following equation can be obtained. ρ acc X acc - σ acc Y acc = U (7) in which X acc = T ssc (Z) [T pitch_acc (z) - 1] a x Y acc = T ssc (Z) [T pitch_acc (z) - 1] ω. y (8th)

U is calculated as follows: U = T adi (Z) [ω y - ω z θ relative ] (9)

Similarly, by equating (2) and (6) for decelerating the vehicle, the following equation can be obtained: ρ dec X dec - σ dec Y dec = U (10) in which X dec = T ssc (Z) [T pitch_dec (z) - 1] a x Y dec = T ssc (Z) [T pitch_dec (z) - 1] ω. y (11)

The following is a summary of the calculation algorithm.

wobei d_xi, n_xi die betroffenen Filterkoeffizienten sind. Man achte, dass die obige Berechnung sowohl für das Beschleunigen als auch für das Abbremsen geeignet ist und dass der Abbremswert als X^dec und der Beschleunigungswert als X^acc mit unterschiedlichen Sets Filterkoeffizienten bezeichnet ist. Wenn sich das Longitudinalbeschleunigungssignal a_x von einem positiven Wert in einen negativen Wert wandelt und den Nullwert zum Zeitpunkt k kreuzt, wird das nachfolgende Rücksetzen verwendet, um die Berechnung von X^dec zu beginnen. Xdeck–1 = Xacck–1 Xdeck–2 = Xacck–2 Xdeck–3 = Xacck–3 (13)und die Berechnung für X^acc angehalten. In ähnlicher Weise, wird, wenn das Longitudinalbeschleunigungssignal a_x sich von einem negativen Wert in einen positiven Wert ändert und den Nullwert zum Zeitpunkt t kreuzt, das nachfolgenden Rücksetzen zum Start der Berechnung von X^acc eingesetzt: Xacct–1 = Xdect–1 Xacct–2 = Xdect–2 Xacct–3 = Xdect–3 (14)und die Berechnung für X^dec angehalten.In step 104 the filtered longitudinal acceleration X is determined in the following iterative equation:

where d _xi , n _{xi are} the affected filter coefficients. Note that the above calculation is suitable for both acceleration and deceleration, and that the deceleration value is designated as X ^dec and the acceleration value as X ^{acc is designated} as different sets of filter coefficients. When the longitudinal acceleration signal a _{x changes} from a positive value to a negative value and crosses the zero value at time k, the subsequent reset is used to begin the calculation of X ^dec . X dec k-1 = X acc k-1 X dec k-2 = X acc k-2 X dec k-3 = X acc k-3 (13) and the calculation for X ^acc stopped. Similarly, if the longitudinal acceleration signal a _x changes from a negative value to a positive value and crosses the zero value at time t, the subsequent reset is used to start the calculation of X ^acc : X acc t-1 = X dec t-1 X acc t-2 = X dec t-2 X acc t-3 = X dec t-3 (14) and the calculation for X ^dec stopped.

In step 106 the filtered pitch acceleration Y is determined by the following equation:

Note that the above calculation is suitable for both acceleration and deceleration, and the corresponding values are referred to as Y ^dec and Y ^acc with different filter coefficient sets. Similar reset schemes as in (13) and (14) for X ^dec and X ^acc are also used here.

wobei

wobei d_ui, n_ui für l = 1, 2, 3, 4 der betroffene zweite Satz Filterkoeffizienten sind.In step 108 the filtered value U in (9) is determined to be:

in which

where d _ui , n _ui for l = 1, 2, 3, 4 are the affected second set of filter coefficients.

Using the calculated value variables X _k ^acc , Y _k ^acc at each sampling time point k (during vehicle acceleration) or the calculated jerk X _t ^dec , Y _t ^dec at each measuring time t (during braking), U _k and U _t , Equation ( 7) and (10) are used to potentially calculate the unknown parameters of the pitch gradient ρ ^acc and ρ ^dec , the pitch acceleration coefficient σ ^acc and σ ^dec .

Since equations (7) and (10) are true when the vehicle is driven on a level ground and there is no wheel in the air (four wheels contact the road), a least mean square (CLS) conditional method can be used. Two different CLS can be used. The first CLS method performs updating of the parameters ρ ^acc or ρ ^dec and σ ^acc or σ ^dec after a predetermined number of coding samples, while the second method updates ρ ^acc or ρ ^dec and σ ^acc or σ ^dec and adds the co-variance matrix resetting every condition test.

Since ρ ^acc or ρ ^dec and σ ^acc or σ ^{dec are} related to the intertial parameters of the pitching motion of the vehicle body, they can be correctly determined by the least squares method only when the vehicle pitch mode is fully excited. The braking actions either due to a request of the driver or a controlled braking request by a stability control system - may be used as such an excitation source. The latter applies to vehicle throttling. Under coasting conditions or when vehicle deceleration is below a threshold during deceleration, least-squares identification is not performed. Considering the steering input of the driver could stimulate both the roll and the pitch dynamics (a sharp curve pushes the vehicle weight in the front direction), consequently, the steering wheel angular speed could also be used to identify conditions for the excitation of pitch mode: δ wvmin ≤ | δ w | ≤ δ wvmax and | δ w | ≥ δ w min (18) where δ _{w is} the measured steering wheel angle, δ _wvmin and δ _{wvmax are} two thresholds to limit the magnitude of the steering wheel _{angular velocity} , δ _{wmin is} a threshold to limit the magnitude of the steering wheel angle. The actual limitation of the upper limit of the steering wheel angular velocity is made due to the consideration that a very fast steering input could generate unrealistic dynamics.

wenn das Fahrzeug abgebremst wird

In step 110 , the conditional sum of the products or cross products of the above filtered variables is determined over a significantly large number of N conditional samples. This was done using the following iterative algorithm, if the first CLS method is used.

when the vehicle is braked

you note that the timing of the time indicated by k and t, itself from the CLS update time, denoted s, different. Only if the conditions are always met, is s = k and t. N in (19) and (20) is the total number of conditional ones Samples for the CLS can be used which has a value between 1000 to 80 000 could have.

step 110 is performed for the conditional sample when the road is a level terrain. Level terrain can then be identified if there is an indication that the vehicle is not on a significantly banqueted road. As a result, checking of the street banquet angle can be used by, for example, employing the method described in US Pat. No. 6,718,248. Terrain level may also be checked via a flatness index (as calculated in US Pat. No. 6,718,248) or a road profile detection (see US Pat. No. 6,718,248) or a rough comparison between the global roll angle and the nominal chassis roll angle.

wobei a_min eine kleine Zahl (beispielsweise 0,0001) ist, welche eingesetzt wird, ein Teilen durch 0 in der durchgeführten Berechnung zu vermeiden; ρ ^acc und ρ ^acc sind die entsprechenden oberen und unteren Grenzen des Nickgradienten, die zu ρ acc = ρacc0 – Δρ ρ acc = ρacc0 + Δρ (22)berechnet werden können und ρ acc / 0 ist der nominale Wert des Nickgradienten (erhalten durch Testen des Fahrzeugs für ein Fahrzeug mit nomineller Beladung); Δρ ist die erlaubte Variation des Nickgradienten; σ ^acc und σ ^acc sind die entsprechenden oberen und unteren Grenzen des Nickbeschleunigungskoeffizienten, der erhalten werden kann als: σ acc = σacc0 – Δσ σ acc = σacc0 + Δσ (23)und σ acc / 0 ist der nominelle Wert des Nickbeschleunigungskoeffizienten (für ein Fahrzeug mit normaler Beladung) Δσ ist die erlaubte Variation des Nickbeschleunigungskoeffizienten. In ähnlicher Weise kann eine Bremsberechnung durchgeführt werden.In step 112 the pitch gradient and the pitch acceleration coefficient are calculated. ρ ^acc and σ ^acc are calculated as follows:

where a _{min is} a small number (e.g., 0.0001) which is used to avoid divide by 0 in the calculation performed; ρ ^acc and ρ ^acc are the corresponding upper and lower bounds of the pitch gradient, which are too ρ acc = ρ acc 0 - Δρ ρ acc = ρ acc 0 + Δρ (22) and ρ acc / 0 is the nominal value of the pitch gradient (obtained by testing the vehicle for a nominal load vehicle); Δρ is the allowed variation of the pitch gradient; σ ^acc and σ ^acc are the corresponding upper and lower limits of the pitch acceleration coefficient, which can be obtained as: σ acc = σ acc 0 - Δσ σ acc = σ acc 0 + Δσ (23) and σ acc / 0 is the nominal value of the pitch acceleration coefficient (for a normal load vehicle) Δσ is the allowed variation of the pitch acceleration coefficient. Similarly, a brake calculation can be performed.

wobei g, γ und v₀ drei positive Zahlen sind, der Zeitpunkt k der reguläre Zeitpunkt und der Zeitpunkt s der konditionelle Zeitpunkt ist. Gleichung (24) wird auch als Covarianzrücksetzen im normalisierten Algorithmus der kleinsten Fehlerquadrate bezeichnet. Während des Abbremsens wird eine ähnliche Rechnung wie (22) durchgeführt.If the second CLS method is used, the pitch gradient ρ and the pitch acceleration coefficient σ can be calculated by the following iterative algorithm. First, during vehicle acceleration a 2 × 2 array variable V _{x + 1} at the (s + 1) th conditional time, from its last value V _s calculated and then the calculated filtered values X _k ^acc and Y _k ^acc, as follows:

where g, γ and v _{0 are} three positive numbers, the time k is the regular time and the time s is the conditional time. Equation (24) is also called covariance reset in the normalized algorithm denoted least squares. During deceleration, a calculation similar to (22) is performed.

The pitch gradient and the pitch acceleration coefficient are calculated using the 2 × 2 matrix V _s and the calculated filtered values X _k , X _k and U _k , as follows for the acceleration case:

A similar Calculation can be for the braking done become.

The calculated values are also limited to their feasibility rates, as in the following case of acceleration: ρ acc s + 1 = sat (ρ acc s + 1 , ρ acc 0 - Δρ, ρ acc 0 + Δρ) σ acc s + 1 = sat (σ acc s + 1 , σ acc 0 - Δσ, σ acc 0 + Δσ) (26) and the following brake case ρ dec t + 1 = sat (ρ dec s + 1 , ρ dec 0 - Δρ, ρ dec 0 + Δρ) σ dec s + 1 = sat (σ dec s + 1 , σ dec 0 - Δσ, σ dec 0 + Δσ)

During the Time when the conditions for (24) and (25) do not apply, the calculations are frozen to their last values.

From the calculated pitch gradient and pitch acceleration coefficient in step 112 , the vehicle load and its distance to the center of gravity of the car body in the vertical direction can be in step 114 be determined.

The variable M _s is the nominal vehicle body mass and the distance of the original center of gravity C _{0 of} the vehicle body from the rear axle is denoted by L which is measured longitudinally parallel to the vehicle floor (see 4 ). If a load of additional mass ΔM is loaded into the trunk or the rear portion of the vehicle and the distance between the center of gravity C _{Δ of} this mass and the rear axle is assumed to be 0, the center of gravity of the vehicle body with the additional mass is likely to change. The longitudinal distance between C ₀ and C is ΔL.

The total pitch moment of inertia of the vehicle body relative to the end (with added mass) center of gravity C can be expressed as I yc = I M yc + I .DELTA.M yc (28) in which I M yc = I YC0 + M s .DELTA.L 2 I .DELTA.M yc = ΔM (L - ΔL) 2 (29)

unter der Annahme, dass der nominelle Nickgradient und der Nickbeschleunigungskoeffizient ρ₀ und σ₀ ist, wird:

wobei K_pich die Nicksteifigkeit aufgrund der Federung bezeichnet und dieser Wert beim Fahrzeugabbremsen und Beschleunigen unterschiedlich ist. Man bezeichnet diese als K_{pich_acc} für das Beschleunigen und K_{pich_dec} für das Abbremsen. Dann gilt für das Beschleunigen des Fahrzeugs

und für das Abbremsen des Fahrzeugs

By substituting (27) in (29), (28) can be expressed as follows:

assuming that the nominal pitch gradient and pitch acceleration coefficient ρ is ₀ and σ is ₀ ,

where K _{pich denotes} the pitching stiffness due to the suspension and this value is different during vehicle braking and acceleration. These are called K _{pich_acc} for acceleration and K _{pich_dec} for braking. Then applies to the acceleration of the vehicle

and for slowing down the vehicle

und für das AbbremsenUsing these nominal values and the calculated values ρ ^dec , σ ^dec and ρ ^acc , σ ^acc , the load mass and the load distance satisfy the following for accelerating:

and for braking

Theoretically, (34) and (35) should be the same, a small difference is possible due to numerical errors. Due to this fact, averaged pitches are used:

Out the relationship in (34) or (35) and the average values in (36) the following estimates the added mass and the position of the added mass become.

In step 116 one of the vehicle systems is controlled. This is a safety system as described above, such as a pitch or roll stability system, or a vehicle body level system 70 , a front light adjustment system 72 and the sensor signal compensation block 74 ,

In step 100 of the 6 For example, a stability control system such as a rollover stability control system or a yaw stability control system is controlled according to the added mass and the height of the loaded masses. The safety system may also be directly controlled by the pitch gradient and pitch acceleration coefficient, both of which may be adaptive. A stability control gain / threshold compensation term may also be generated based on the pitch gradient, the pitch acceleration coefficient, or the loaded trunk space. The threshold may be changed to allow for earlier firing if additional mass at a predetermined location in step 114 is detected. The compensation amount is likely to be determined experimentally based on the vehicle configuration.

If the vehicle has a significant load, namely the calculated load exceeds a threshold P _max ΔM ≥ P Max (38) and at the same time the longitudinal distance of the mass exceeds a further threshold L _max L ≥ L Max (39) the vehicle tends more to oversteer. In this case, the yaw stability control gains and the side slip angle control gains must be increased to achieve early activation to prevent the vehicle from experiencing uncontrollable and unstable dynamics. Control _gains put the value G _TLMAX on the tip, which is set for large trunk _loadings .

If the vehicle has a significant payload, namely ΔM ≥ P _max , but this payload is not in the vehicle trunk, ie, that the longitudinal distance of the Zulandung is less than the smallest threshold L _min L ≤ L min (40) For example, all the feedback control gains used to command the actuators are set to a value set G _NTLMAX set for large payloads, not in the trunk.

If the vehicle has a significant payload, namely ΔM ≥ P _max , but the payload distance is between the trunk space and 0, ie L is between a lower threshold L _min (possibly 0) and an upper threshold Lmax L min ≤ L ≤ L Max (41) For example, all the feedback control gains used to command the actuators are set to the following values which are set according to the detected load height, as follows:

If the vehicle has a payload below the permitted payload P _max but above the lower limit of a permissible luggage load P _min , namely P min ≤ ΔM ≤ P Max (43)

It is assumed that all nominal gains for the feedback (for a nominal load vehicle) are referred to as g _nom , then the control gains are adjusted based on the detected payload, as follows:

wobei ρ_min dem einem Fahrzeug ohne Kofferraumzuladung entsprechende Nickgradient ρ_max der dem Fahrzeug mit maximal erlaubter Kofferraumzuladung entsprechende Nickgradient und ρ_max der dem Fahrzeug mit einer maximal erlaubten Kofferraumzuladung entsprechenden Nickgradienten entspricht.The pitch gradient itself can also be used directly to adjust control gains. If the vehicle has a significant pitch gradient increase, ρ ≥ ρ _min , all the feedback control gains used to command the actuators are set to the subsequent values based on the detected pitch gradient, as follows:

where ρ _min corresponding to a vehicle without boot capacity corresponding pitch gradient ρ _max of the vehicle with maximum allowable boot capacity corresponding pitch gradient and ρ _max corresponding to the vehicle with a maximum allowable trunk load pitch gradient.

you note that other control gain settings, except the above linear interpolation method, are possible. Also note that the dead zones and thresholds that in a stability feedback control be used, even in similar Way on the basis of the load distance L and / or the load .DELTA.M or Nick gradients or the pitch moment of inertia, as calculated in (32).

wobei b die Fahrzeugbasis ist, N_f0, N_r0 nominelle Normallasten auf der Front- und Hinterachse, wenn das Fahrzeug keine Kofferraumzuladung besitzt, L₀ der Abstand vom nominalen Schwerpunkt des Fahrzeugs zur Hinterachse. Die durch die nominelle Last generierte Nickabweichung des Fahrzeugs kann berechnet werden zu:

wobei K_f, K_r die vertikalen Federungsraten für die Front- und Hinterachsen sind.With the additional trunk load, the front and rear normal loads can be calculated to:

where b is the vehicle base, N _f0 , N _{r0 are} nominal normal _loads on the front and rear axles when the vehicle has no trunk load, L _{0 is} the distance from the nominal center of gravity of the vehicle to the rear axle. The pitch deviation of the vehicle generated by the nominal load can be calculated as:

where K _f , K _{r are} the vertical suspension rates for the front and rear axles.

For a well-adjusted vehicle, such a nominal payload-induced pitch deviation is usually 0, d. h φ _LPM0 = 0.

The payload-induced pitch deviation caused by a boot load can be calculated in a similar manner to:

In 74 For example, the deviation Δφ _LPM between φ _LPM0 and φ _LPM can be used to correct the sensor _readings , as follows: ω xcorrected = ω x cos (Δφ LPM ) - ω z sin (Δφ LPM ) ω zcorrected = ω x sin (Δφ LPM ) + ω z cos (Δφ LPM ) a xcorrected = a x cos (Δφ LPM ) - a z sin (Δφ LPM ) a zcorrected = a x sin (Δφ LPM ) + a z cos (Δφ LPM ) (49) where ω is _xcorrected , ω is _zcorrected , a is _xcorrected , a _{zcorrected is} the corrected roll rate, yaw rate, longitudinal _acceleration , and vertical _acceleration . Note that it follows from (49) that if the vehicle merely yaws without rolling, the roll rate sensor mounted on the vehicle may still have a roll rate output.

The load-induced pitch deviation calculated above can be found in 70 . 72 can be used to obtain the desired control functions.

While the Invention described with reference to preferred embodiments and explained were, are a variety of deviations and alternative designs obvious to the skilled person. Accordingly, the invention should only by the scope of the claims be limited.

10

motor vehicle

10A

vehicle body

10B

wheel axle

11

road surface

12A

front right tire

12B

front left tire

13A

rear right tire

13B

rear left tire

14A

control systems

14B

Rear steering system

16

measuring system

18

control system

20

speed sensor

22

vehicle frame

24

inertial frame

26

control

28

Yaw rate sensor

32

lateral acceleration

33

Vertical acceleration sensor

34

Roll angular rate sensor

35

Steering wheel (hand wheel) angle measurement system

36

Angular acceleration sensor

37

Pitch rate sensor

38

position sensor

40

Spring load sensor

42

Suspension position sensor

44

safety device

45

air bag

46A

Control actuator

46B

Control actuator

46C

Control actuator

46D

Control actuator

48

suspension control

50

signal multiplexer

52

Radabhebedetektor

54

Vehicle roll angle calculator

56

Roll Stability Control (RSC) feedback control command

57

torque control

58

load detector

60

brake control

62A

right front brake

62B

left front brake

62C

left rear brake

62D

right rear brake

66

Yaw stability control system

68

Traction control system

70

Body level system

72

Frontlichteinstellsystem

74

Sensor signal compensation block

80

load floor

84

box

86

first filter

88

Pitch acceleration coefficient determination module

90

second filter

92

Z determination module

94

third filter

96

Loading loading position detection block

98

Charging characterization block

100

step

102

step

103

step

104

step

106

step

108

step

110

step

112

step

114

step

116

step

Claims (12)

Method for controlling a vehicle system with: - Determine an adaptive pitch acceleration coefficient; and - Taxes of the vehicle system according to the adaptive pitch acceleration coefficient Method according to claim 1, characterized in that that the determination of an adaptive pitch acceleration coefficient the determination of an adaptive pitch acceleration coefficient corresponding to a longitudinal acceleration, a pitch rate, a Pitch acceleration, a yaw rate and a reactive roll angle includes. Method for controlling a vehicle system with: - To generate a pitching signal that is for the pitch rate of the vehicle is indicative; - Determine an added mass according to the pitch rate signal; - classifying the longitudinal Place of the added Mass in boot load or non-boot load; and - Taxes of the vehicle system according to the metered mass and the longitudinal location and / or the trunk load. The method of claim 3, further characterized by determining a longitudinal acceleration, a relative acceleration Roll angle and a yaw rate, wherein the determination of the added mass determining the added Mass according to the pitch rate signal, the longitudinal acceleration, includes the relative roll angle and a yaw rate. The method of claim 3, further characterized by determining the position of the added mass, wherein the controlling, controlling the safety system according to the added mass and the longitudinal distance of the added mass. Method according to claim 3, wherein the position of the added Measure the position of the center of gravity of the vehicle with added mass includes. Method for controlling a vehicle system with: - Determine a pitch gradient; - Determine a pitch acceleration coefficient; - Determine an added mass and the position of the added Mass of pitch gradient and pitch acceleration coefficient; and - Taxes the vehicle system according to the added mass and position of added Dimensions. The method of claim 7, wherein controlling the Vehicle system includes controlling a security system, including Controlling a roll stability control system. Method according to claim 7, characterized in that controlling the security system is controlling a yaw stability control system includes. The method of claim 7, wherein controlling the Vehicle system comprising controlling a front light adjustment system. The method of claim 7, wherein controlling the Vehicle system controlling the vehicle body level system includes. The method of claim 7, wherein the determination a pitch acceleration coefficient determining the pitch acceleration coefficient in accordance with a longitudinal acceleration signal, a yaw rate signal and a pitching speed.